The present invention relates to a solvent leak detecting sensor.
Water detecting sensors are the most widely known type of solvent detecting sensor. A structure which is commonly used for the detecting network in such water detecting sensors is one in which a pair of conductors, which form part of a detection circuit, are installed on an insulating substrate so that the conductors are exposed, and so that the conductors are separated from each other. In the case of water detecting sensors which use a structure of this type, an electrical change occurs in the detection circuit when the pair of conductors in the abovementioned detecting network are short-circuited by water. Accordingly, water leakage can be detected by detecting this electrical change.
However, in cases where it is desired to detect a solvent such as methyl ethyl ketone (herein, MEK), there is currently no solvent detecting sensor available which is able to detect such a solvent exclusively. Accordingly, the abovementioned water detecting sensors have been used as a substitute in order to detect such solvents. In such cases, since most solvents generally have a lower electrical conductivity than water, the water sensors must be modified so that their sensitivity is increased.
In cases where a water detecting sensor of the above type is used as a substitute in order to detect a solvent, e.g., in cases where such a sensor is used to monitor solvent leakage in a chemical plant or the like, the sensor is still primarily a water sensor. Even if there is no solvent leakage, the pair of conductors in the water detecting sensor may be short-circuited as a result of being wet by rain or other water. Thus, accurate monitoring of solvent leakage cannot be guaranteed using such a sensor.
Even if the sensitivity of a water detecting sensor is increased as described above, there are limits ot how far this sensitivity can be increased, and it is difficult to achieve a detection sensitivity which is sufficient for a reliable solvent detecting sensor.
The present invention was designed in light of the problems encountered in the known devices. An object of the present invention is to provide a solvent leak detecting sensor which is able to detect solvents as its primary detection target and which has a good detectionsensitivity.